Many measuring systems for biochemical analytics comprise components of clinical analytical methods. Such systems generally include the measurement of analytes, e.g., metabolites or substrates, for example, which may be determined directly or indirectly with the aid of an enzyme. For example, an analyte of interest may be converted into another compound with the aid of an enzyme-coenzyme complex and subsequently quantified via this enzymatic reaction. In such process, the analyte to be determined may be brought into contact with a suitable enzyme and a coenzyme, under appropriate reaction conditions, whereby the coenzyme changes, e.g., is oxidized or is reduced by the enzymatic reaction. Such changes may be detected electrochemically or photometrically either directly or by means of a mediator. Further, a calibration curve may be constructed to provide a direct correlation between the measured value (of the detected change) and the change detected for known concentrations of the analyte of interest, thereby facilitating determination of the analyte's concentration.
Coenzymes, in general, comprise molecules which may be covalently or non-covalently bound to an enzyme and that themselves may be changed by the conversion of the analyte. By way of example, coenzymes include nicotinamide adenine dinucleotide (“NAD”) and nicotinamide adenine dinucleotide phosphate (“NADP”), from which NADH and NADPH, respectively, are formed by an enzyme catalyzed reduction.
As described in US 2008/0213809, at least some of the disadvantages of conventional measuring systems, for example limited shelf-life and special storage condition requirements (such as cooling or dry storage) required in order to achieve improved shelf-life, may be abviated by using the stable NAD/NADH and NADP/NADPH derivatives disclosed therein. These NAD(P)H analogues may aid in reducing the occurrence of erroneous results resulting from the inadvertent use of degraded co-factors in critical assays. The use of NAD/NADH and NADP/NADPH derivatives that exhibit increased stability can be of utility especially when critical tests which are carried out by end-users such as patients performing glucose self-monitoring.
As described in US 2008/0213809 the chemical synthesis of carba-NAD is extremely challenging, involving a process that includes at least 8 steps. These processes generally provide relatively low yields, and are quite expensive. A representative chemical route for the synthesis of carba-NAD is depicted in FIG. 1. Accordingly, there is a need for alternative methods of synthesizing carba-NAD. Ideally these alternative methods should be less cumbersome, provide larger yields, and be more cost-effective than are the organic chemistry based methods currently in use. Some aspects of the instant disclosure seek to address this need.